1. Field of the Invention
The present invention relates to a method of manufacturing a polymer for lithography, a method of manufacturing a resist composition using the polymer for lithography obtained from the above method, and a method of manufacturing a substrate having a pattern using the resist composition.
Priority is claimed on Japanese Patent Application No. 2013-166657, filed Aug. 9, 2013, the content of which is incorporated herein by reference.
2. Description of Related Art
Recently, by virtue of the advance in lithography technology, fine-fabrication of a resist pattern formed in a process of manufacturing a semiconductor device, a liquid crystal device, and the like, is increasingly proceeding. According with that, high purity of a polymer for lithography used for a lithography process is required.
A polymer for lithography is generally prepared by a method of obtaining a polymerization reaction solution including a polymer by polymerizing monomers in the presence of a polymerization solvent. In the polymerization reaction solution to be obtained, the unnecessary components such as un-reacted monomers are dissolved in a polymerization solvent in addition to a polymer. Therefore, in order to remove these components, a purification method using a re-precipitation method is known, in which the method includes precipitating the polymer by mixing the polymerization reaction solution with a poor solvent, and then solid-liquid-separating.
Patent Document 1 discloses a method of removing a poor solvent, in which since a wet powder, which is obtained by precipitating the polymers by adding a polymerization reaction solution to the poor solvent, and then, solid-liquid-separating, generally includes about 60 to 70% by weight of the poor solvent used for a precipitation operation, the wet powder is dissolved in a solvent for a resist through washing the wet powder with water, and then distilled for removing the poor solvent.
Examples in Patent Document 2 disclose a method of concentrating a wet powder, in which a liquid-containing rate in the wet powder obtained by adding a polymerization reaction solution to a poor solvent, and then performing centrifugation is about 64 to 73% by weight, and the wet powder is concentrated by a vacuum distillation after dissolving it in a glycol-based solvent.
Examples in Patent Document 3 disclose a method of performing a re-slurry process, in which a wet powder, which is obtained by adding a polymerization reaction solution to a poor solvent, and then solid-liquid-separating, is re-mixed with a poor solvent, and then solid-liquid-separated.